Position detection device detecting a position of target object and a position detection program

Abstract

A position detection device obtains image coordinate groups representing a coordinate of a target object in each acquired image having first and second acquired image groups. The first acquired image group has acquired images obtained at an image acquiring timing in a reference period. The second acquired image group has acquired images obtained at an image acquiring timing in the reference period, which is delayed from the image acquiring timing of the first acquired image group by an asynchronous time. The device performs a Fourier transformation of each of a first locus and a second locus, and calculates a first frequency waveform based on the first locus and a second frequency waveform based on the second locus. The device calculates a position of the target object based on a relationship in which the frequency waveforms are delayed relative to each other by a phase corresponding to the asynchronous time.

What is claimed is: 
     
       1. A position detection device capable of detecting a position of a target object in an acquired image on the basis of a plurality of acquired images acquired by a plurality of projection cameras, comprising:
 an image coordinate group acquiring section obtaining an image coordinate group representing a coordinate of the target object in each of the acquired images, 
 the acquired images forming a first acquired image group and a second acquired image group, 
 the first acquired image group comprised of a plurality of acquired images which are acquired by a first projection camera in the plurality of projection cameras at a first image acquiring timing every predetermined reference period, 
 the predetermined reference period representing a predetermined fixed period, 
 the second acquired image group which is acquired by a second projection camera which is different from the first projection camera at a second image acquiring timing every predetermined reference period, 
 the image acquiring timing of the second acquired image group being delayed from the image acquiring timing of the first acquired image group by an asynchronous time, and the first acquired image group and the second acquired image group forming a parallel stereo relationship; 
 a frequency waveform calculation section performing a Fourier transformation of each value obtained by dividing each of a first locus and a second locus by a projection depth of the first projection camera and a projection depth of the second projection cameras, respectively, and calculating a first frequency waveform on the basis of the first locus and a second frequency waveform on the basis of the second locus, the first locus representing a transition along a time series of the image coordinate group obtained from the first acquired image group, and the second locus representing a transition along a time series of the image coordinate group obtained from the second acquired image group; and 
 a position calculation section obtains a matrix containing a virtual position of the target object on the basis of a relationship between the first frequency waveform and the second frequency waveform which are delayed relative to each other by the asynchronous time, and calculates a position of the target object by dividing the virtual position of the target object with elements in the obtained matrix. 
 
     
     
       2. The position detection device according to  claim 1 , further comprising a distance calculation section calculating a distance to the target object on the basis of the position of the target object. 
     
     
       3. The position detection device according to  claim 1 , wherein the image coordinate group acquiring section acquires the image coordinate group on the basis of each of the first acquired image group acquired by the first projection camera and the second acquired image group acquired by the second projection camera, where the first projection camera and the second projection camera are arranged in parallel to each other. 
     
     
       4. A non-transitory computer-readable storage medium for storing a program for performing a function of the position detection device according to  claim 1 . 
     
     
       5. A position detection device detecting a position of a target object in an acquired image on the basis of a plurality of acquired images acquired by a plurality of projection cameras, the position detection device comprising:
 an image coordinate group acquiring section obtaining an image coordinate group composed of image coordinates representing a coordinate of the target object in each of the acquired images, 
 the acquired images forming a first acquired image group and a second acquired image group, 
 the acquired images in the first acquired image group acquired by a first projection camera of the plurality of projection cameras at a first image acquiring timing every predetermined reference period, the predetermined reference period representing a predetermined fixed period, 
 the acquired images in the second acquired image group acquired by a second projection camera of the plurality of projection cameras which is different from the first projection camera at a second image acquiring timing every predetermined reference period, 
 the second image acquiring timing is delayed from the first image acquiring timing by an asynchronous time; and 
 the first projection camera and the second projection camera are arranged in parallel to each other, and the first acquired image group and the second acquired image group forming a parallel stereo relationship; 
 a position calculation section calculating a position of the target object on the basis of each of the acquired images in the first image coordinate group and the second image coordinate group and a relationship in image acquiring timing between the first acquired image group and the second acquired image group which are delayed relative to each other by the asynchronous time, 
 performing a Fourier transformation of each value obtained by dividing each of a first locus and a second locus by a projection depth of the first projection camera and the projection depth of the second projection cameras, respectively, 
 obtaining a first frequency element of the first locus of the position of the target object in a real space on a basis of a relationship between the image coordinates representing the position of the target object in the real space and 
 obtaining a second frequency element of the second locus of the position of the target object, 
 obtaining a matrix containing a virtual position of the target object on the basis of a relationship between the first frequency element and the second frequency element which are delayed relative to each other by the asynchronous time, and 
 calculating the position of the target object on the basis of the obtained first frequency element and the obtained second frequency element with elements in the obtained matrix. 
 
     
     
       6. The position detection device according to  claim 5 , further comprising a distance calculation section calculating a distance to the target object on the basis of the position of the target object. 
     
     
       7. The position detection device according to  claim 5 , wherein the image coordinate group acquiring section acquires the image coordinate group on the basis of each of the acquired image groups acquired by the projection cameras which are arranged in parallel to each other. 
     
     
       8. A non-transitory computer-readable storage medium for storing a program for performing a function of the position detection device according to  claim 5 . 
     
     
       9. The position detection device according to  claim 5 , wherein the projection cameras have a non-linear projection model. 
     
     
       10. The position detection device according to  claim 5 , wherein the projection cameras provide non-linear data.